Optical unit, backlight assembly having the same and display device having the same

ABSTRACT

An optical unit includes a base, a light-condensing member disposed on the base to condense a first portion of light that is incident onto the base and protrusion members disposed on a surface of the light-condensing member to scatter a second portion of the light that is incident onto the base. A backlight assembly includes light sources, an optical unit receiving light from the light sources to condense and scatter the light, and may also include an optical member disposed over the optical unit to enhance the front luminance of the light. A display device includes light sources, an optical module and a display panel. Thus, display quality of the display device may be enhanced.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a reissue application from U.S. patent applicationSer. No. 12/235,989 filed on Sep. 23, 2008 and issued as U.S. Pat. No.7,677,784, which is a continuation of U.S. patent application Ser. No.11/393,281, filed Mar. 29, 2006, now U.S. Pat. No. 7,438,459 whichclaims priority of Korean Patent Application No. 2005-3460510-2005-0034605 filed on Apr. 26, 2005, the contents of which are hereinincorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an optical unit, a backlight assemblyhaving the optical unit and a display device having the optical unit.More particularly, the present invention relates to an optical unitcapable of condensing and diffusing light, a backlight assembly havingthe optical unit and a display device having the optical unit.

2. Description of the Related Art

Generally, a backlight assembly of a display device is classified aseither all edge illumination type backlight assembly or a directillumination type backlight assembly.

The edge illumination type backlight assembly includes a light guidingplate and a lamp disposed at a side of the light guiding plate. The edgeillumination type backlight assembly is usually employed in a displaydevice having a relatively small display size. The edge illuminationtype backlight assembly has many merits, such as good opticaluniformity, long lifetime, small size, etc.

The direct illumination type backlight assembly has been developed asthe size of liquid crystal display (LCD) devices has increased overtime. The direct illumination type backlight assembly includes aplurality of lamps disposed under a light-diffusing plate and arrangedsubstantially parallel to each other. The direct illumination typebacklight assembly includes more lamps than the edge illumination typebacklight assembly, and thus has a relatively high luminance.

However, in a direct illumination type backlight assembly, the lampconfiguration may be detected through the light-diffusing plate.Therefore, the display quality of a display device employing a directillumination type backlight assembly may be lower than the displayquality of a display device employing an edge illumination typebacklight assembly.

SUMMARY OF THE INVENTION

Systems and techniques provided herein may reduce or eliminate drawbacksof existing direct illumination type backlight assemblies. Inembodiments of the invention, an optical unit configured to condense anddiffuse externally-provided light is disclosed.

Embodiments of the present invention also provide a backlight assemblyhaving the above-mentioned optical unit to irradiate light havingenhanced luminance uniformity.

Embodiments of the present invention also provide a display devicehaving the above-mentioned backlight assembly.

In one aspect of the present disclosure, an optical unit includes abase, a light-condensing member and a plurality of protrusion members.The light-condensing member is disposed on the base to condense a firstportion of light that is incident onto the base. The protrusion membersare disposed on a surface of the light-condensing member to scatter asecond portion of the light that is incident onto the base.

The light-condensing member may include a first slant face and a secondslant face. The first slant face protrudes from the base to form a firstobtuse angle with respect to the base. The second slant face protrudesfrom the base and is slanted toward the first slant face.

The light-condensing member optionally includes a third slant face and afourth slant face. The third slant face extends from an upper portion ofthe first slant face to form a second obtuse angle. The fourth slantface extends from an upper portion of the second slant face andconnected to the third slant face.

The light-condensing member optionally includes a horizontal facesubstantially parallel to the base and connected to the first and secondslant faces.

In another aspect of the present disclosure, a backlight assemblyincludes a light source, an optical unit and an optical member. Thelight source generates light. The optical unit includes alight-condensing portion and a protrusion portion. The light-condensingportion is disposed on a base to condense a first portion of the lightgenerated from the light source. The protrusion portion is disposed on asurface of the light-condensing portion to scatter a second portion ofthe light generated from the light source. The optical member receiveslight from the optical unit and is configured to emit light havingsubstantially uniform luminance with respect to a front direction of thebase.

The backlight assembly may include a plurality of light sources. Imagesof the light sources, which have a second number that is greater than afirst number of the light sources, are formed between the optical unitand the optical member. The light-condensing portion may have variousshapes. The light-condensing portion, for example, includes slant faces.A portion at which slant faces and the base are connected and a portionat which slant faces are connected with each other may have a roundedportion having a predetermined radius of curvature.

In still another aspect of the present disclosure, a display deviceincludes a plurality of light sources, an optical module and a displaypanel. The light sources generate light, and have a first number. Theoptical module receives the light from the light sources to form imagesof the light sources. The images have a second number that is greaterthan the first number. The optical module may emit light havingsubstantially uniform luminance with respect to a front direction of theoptical module. The display panel is disposed over the optical module todisplay an image using light from the optical module.

According to the above, images of light sources, the number of which maybe at least double of the number of the light sources, are formedbetween the optical unit and the optical member, and light emitted fromthe light sources diffuses through the optical unit. Thus, bright linesgenerated on the optical member may be reduced, and display quality ofthe display device having the optical unit may be enhanced.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other advantages of the present invention will becomereadily apparent by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings wherein:

FIG. 1 is a cross-sectional view illustrating a portion of an opticalunit according to an exemplary embodiment of the present invention;

FIG. 2 is a cross-sectional view illustrating a portion of an opticalunit according to another exemplary embodiment of the present invention;

FIG. 3 is a cross-sectional view illustrating a portion of an opticalunit according to still another exemplary embodiment of the presentinvention;

FIG. 4 is a cross-sectional view illustrating a portion of an opticalunit according to still another exemplary embodiment of the presentinvention;

FIG. 5 is a cross-sectional view illustrating a portion of a backlightassembly according to an exemplary embodiment of the present invention;

FIG. 6 is a plan view illustrating a portion of lamps viewed through anoptical unit shown in FIG. 5;

FIG. 7 is a cross-sectional view illustrating a position of a lamp imageformed over an optical unit of the backlight assembly shown in FIG. 5;

FIG. 8 is a graph illustrating a relationship between a first distance‘Z’ and a second distance ‘D’ in FIG. 7; and

FIG. 9 is a cross-sectional view illustrating a display device accordingto an exemplary embodiment of the present invention.

DESCRIPTION OF THE EMBODIMENTS

The present invention now will be described more fully hereinafter withreference to the accompanying drawings, in which embodiments of theinvention are shown. This invention may, however, be embodied in manydifferent forms and should not be construed as limited to theembodiments set forth herein; rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullydescribe the invention to those skilled in the art. Like referencenumerals refer to similar or identical elements throughout.

Optical Unit

FIG. 1 is a cross-sectional view illustrating a portion of an opticalunit according to an example embodiment of the present invention.

Referring to FIG. 1, an optical unit 130 includes a base 131, a lightcondenser such as light-condensing member 133, and protrusion members139.

The base 131 serves as a body of the optical unit 130. The base 131 mayinclude a transparent material having a high optical transmissivity, forexample, base 131 may include a material such as polyethyleneterephthalate (PET).

The light-condensing member 133 is disposed on or over the base 131. Thelight-condensing member 133 may have various shapes. For example, thelight-condensing member 133 may have a rod shape that is elongated alongone direction, and may have a substantially polygonal cross section(e.g., a substantially triangular cross section as shown in FIG. 1). Theoptical unit may include a plurality of light condensing members 133,and the light condensing members are disposed substantially parallel toeach other. The light-condensing member 133, for example, may include amaterial that is substantially the same material as that of the base131. The light-condensing member 133 may include polymethyl methacrylate(PMMA), which has advantageous characteristics such as good heatresistance, high optical transmissivity, good chemical resistance, etc.

As noted above, a cross-section of the light-condensing member 133,which is substantially perpendicular to a longitudinal direction of thelight-condensing member 133, may have a polygonal shape. Thelight-condensing member 133 may have various geometrical structures forchanging an optical path of light provided into the optical unit 130toward a front direction of the optical unit 130.

In some embodiments, the light-condensing member 133 includes a firstslant face 134 and a second slant face 135. The first slant face 134protrudes from the base 131 to form a first obtuse angle θ1 with respectto the base 131. The second slant face 135 protrudes from the base 131and faces the first slant face 134. The second slant face 135 is slantedtoward the first slant face 134.

As shown in FIG. 1, the first slant face 134 and the second slant face135 are substantially symmetrical to each other with respect to a planethat is substantially perpendicular to the base 131. The first andsecond slant faces 134 and 135 are elongated along the longitudinaldirection of the light-condensing member 133 (into the page of FIG. 1).

In order to effectively condense the light provided into the base 131toward the front direction of the optical unit 130, the first and secondslant faces 134 and 135 may preferably form an angle φ of about thirtydegrees to about one hundred fifty degrees.

The first and second slant faces 134 and 135 are connected with eachother at a top portion, and the top portion may be rounded. The firstand second slant faces 134 and 135 are connected with base 131 at abottom portion, and the bottom portion may be rounded.

When the top portion and the bottom portion, at which the base 131, thefirst slant face 134 and the second slant face 135 are connected witheach other, have a rounded portion, light may effectively diffusethrough the rounded portion. Thus, compared to a configuration where theportion is not rounded, the appearance of bright lines (when viewed overthe optical unit 130) may be reduced.

The rounded portion of the top portion and the bottom portion maypreferably have a radius of curvature in a range of about 0.05 times toabout 0.7 times a pitch of the light-condensing member 133. The pitch Pof the light-condensing member 133 is defined as an interval betweenneighboring top portions or between neighboring bottom portions (asindicated in the example illustrated in FIG. 1).

In the embodiment shown in FIG. 1, the light-condensing member 133includes the first and second slant faces 134 and 135 that comprisegenerally flat surfaces. Alternatively, the light-condensing member 133may include a slant face comprising a curved surface. For example, thelight-condensing member 133 may include a first curved slant face thatprotrudes from the base 131 and a second curved slant face thatprotrudes from the base 131 and is connected to the first curved slantface. At least one of the first and second curved slant faces may beconvex. Further, at least one of the first and second curved slant facesmay be concave.

The protrusion members 139 protrude from a surface of light-condensingmember 133. The protrusion members 139 cover a portion of the surface ofthe light-condensing member 133. A protruded amount and a protruded sizeof each protrusion member 139 may be varied. The protrusion members 139are formed such that the light-condensing member 133 has a surfaceroughness of about 0.1 to about 10 micrometers root mean square.

FIG. 2 is a cross-sectional view illustrating a portion of an opticalunit according to another exemplary embodiment of the present invention.

Referring to FIG. 2, an optical unit 230 includes a base 231, alight-condensing member 233 and protrusion members 239. The exemplaryoptical unit 230 shown in FIG. 2 is substantially identical to theexemplary optical unit 130 shown in FIG. 1 except for the number ofslant faces of the light-condensing member 233.

The light-condensing member 233 includes first, second, third and fourthslant faces 234, 235, 236 and 237, which are elongated along alongitudinal direction of the light-condensing member 233 (into the pageof FIG. 2).

The first slant face 234 protrudes from the base 231 to form a firstobtuse angle θ2 with respect to the base 231. The second slant face 235protrudes from the base 231 and faces the first slant face 234. Thesecond slant face 235 is slanted toward the first slant face 234. Asshown in FIG. 2, the first slant face 234 and the second slant face 235are substantially symmetrical to each other with respect to a plane thatis substantially perpendicular to the base 231 (i.e., a plane thatextends vertically and into the page of FIG. 2).

The third slant face 236 extends from an upper portion of the firstslant face 234 to form a second obtuse angle θ3 with respect to the base231. The fourth slant face 237 extends from an upper portion of thesecond slant face 235 and is thus connected to the third slant face 236.As shown in FIG. 2, the third slant face 236 and the fourth slant face237 are substantially symmetrical to each other with respect to a planethat is substantially perpendicular to the base 231 (i.e., a plane thatextends vertically and into the page of FIG. 2).

The first obtuse angle θ2 and the second obtuse angle θ3 are differentfrom one another. As shown in FIG. 2, the second obtuse angle θ3 isgreater than the first obtuse angle θ2. The third and fourth slant faces236 and 237 may preferably form an angle φ of about thirty degrees toabout one hundred fifty degrees.

The first and second slant faces 234 and 235 are connected with base 231at a bottom portion, and the third and fourth slant faces 236 and 237are connected with each other at a top portion. The bottom portion andthe top portion may be rounded to have a predetermined radius ofcurvature.

FIG. 3 is a cross-sectional view illustrating a portion of an opticalunit 330 according to still another exemplary embodiment of the presentinvention.

Referring to FIG. 3, an optical unit 330 includes a base 331, alight-condensing member 333 and protrusion members 339. Thelight-condensing member 333 includes first, second, third and fourthslant faces 334, 335, 336 and 337.

In the exemplary embodiment shown in FIG. 3, the optical unit 330 issubstantially identical to the exemplary optical unit 230 shown in FIG.2 except for a first angle θ4 being greater than a second angle θ5.Here, the first slant face 334 and the second slant face 335 form thefirst angle θ4 with respect to the base 331, and the third slant face336 and the fourth slant face 337 form the second angle θ5 with respectto the base 331.

FIG. 4 is a cross-sectional view illustrating a portion of an opticalunit 430 according to still another exemplary embodiment of the presentinvention.

Referring to FIG. 4, an optical unit 430 includes a base 431, alight-condensing member 433 and protrusion members 439.

The light-condensing member 433 is disposed on a surface of the base431. The light-condensing member 433 includes a first slant face 434, asecond face 435 and a horizontal face 436.

The first slant face 434 protrudes from the base 431 to form a firstobtuse angle θ6 with respect to the base 431. The second slant face 435protrudes from the base 431 and faces the first slant face 434. Thesecond slant face 435 is slanted toward the first slant face 434. Asshown in FIG. 4, the first slant face 434 and the second slant face 435are substantially symmetrical to each other with respect to a plane thatis substantially perpendicular to the base 431 (i.e., a plane thatextends vertically and into the page of FIG. 4).

The horizontal face 436 is substantially parallel to the base 431. Afirst end portion of the horizontal face 436 is connected to an upperportion of the first slant face 434, and a second end portion of thehorizontal face 436, which faces the first end portion, is connected toan upper portion of the second slant face 435.

Backlight Assembly

FIG. 5 is a cross-sectional view illustrating a portion of a backlightassembly 100 according to an exemplary embodiment of the presentinvention.

Referring to FIG. 5, a backlight assembly 100 includes a plurality oflight sources 110, an optical unit 130 and an optical member 150. Theoptical unit 130 shown in FIG. 5 is substantially identical to theoptical unit 130 shown in FIG. 1. Thus, the same reference numerals willbe used to refer to the corresponding parts and further descriptionconcerning the corresponding parts may be omitted. Hereinafter, thelight-condensing member 133 referred to in the description associatedwith FIG. 1 will be referred to as a light-condensing portion, and theprotrusion member 139 referred to in the description associated withFIG. 1 will be referral to as a protrusion portion.

The light sources 110 may include at least one of a fluorescent lamp, asurface light source, and a light emitting diode. The backlight assembly100, for example, includes lamps 110 having a substantially linear andtubular shape. The lamps 110 are substantially parallel to each other.

In some embodiments, each of the lamps 110 includes a lamp tube andelectrode parts. The lamp tube, for example, includes glass. Afluorescent material is coated on an inner surface of the lamp tube, anddischarge gas is charged in an inner space of the lamp tube. A dischargevoltage (which may be provided externally) is applied to the electrodeparts, so that the discharge gas generates light having a wavelengthoutside the visible spectrum. The fluorescent material converts thelight into visible light (light having a wavelength in the visiblespectrum).

The optical unit 130 changes an optical path of a first portion of lightprovided from the lamps to face a front direction of the optical unit130, and scatters a second portion of the light provided from the lamps,as described further below. The optical unit 130 is spaced apart fromthe lamps 110 by a predetermined distance, and includes a base 131, alight-condensing portion 133 and protrusion portions 139.

FIG. 6 is a plan view illustrating a portion of lamps viewed through anoptical unit such as optical unit 130 shown in FIG. 5.

Referring to FIGS. 5 and 6, the light emitted from the lamps 110 isincident onto the base 131 of the optical unit 130. A portion 134A ofthe incident light passes through a region of first slant face 134 onwhich protrusions are not formed, while a portion 135A of the incidentlight passes through a region of second slant face 135 on whichprotrusion portions 139 are not formed. For convenience, the descriptionbelow will be based on a cross-section of the light-condensing portion133 which is substantially perpendicular to the longitudinal directionof the light-condensing portion 133 (such as the cross sectionillustrated in FIG. 5).

When the portion 134A is incident onto the first slant face 134 at apredetermined clockwise angle with respect to a normal line to the firstslant face 134, the light is refracted such that the direction of thetransmitted light is more aligned with a front direction F of the base131.

When the portion 134A is incident onto the first slant face 134 at apredetermined counterclockwise angle with respect to a normal line tothe first slant face 134, the light is refracted such that the directionof the transmitted light is less aligned with the front direction of thebase 131. Light passing through the protrusion portions 139 isscattered.

As a result, for each of the lamps 110, there are two positions at whichlight is condensed in the front direction of the optical unit 130. Twolamp images 111 are formed at the two positions associated with each ofthe lamps 110, so that the number of lamp images 111 is twice the numberof lamps 110.

Lamp images 111 are formed over the optical unit 130. Since a portion ofthe incident light diffuses when exiting through the protrusion portions139, a second luminance of the lamp images 111 is reduced compared to afirst luminance of the associated lamp of the lamps 110.

The optical member 150 receives light from the optical unit 130, andemits light having enhanced optical characteristics; for example,enhanced luminance uniformity. In some embodiments, the optical member150 is separated from the optical unit 130 by a sufficient distance sothat the lamp images 111 are formed between the optical unit 130 and theoptical member 150. The optical member 150, for example, includes a basebody, diffusion beads disposed on the base body to diffuse incidentlight, and binders disposed between the diffusion beads to fasten thediffusion beads to the base body.

As noted above, the second number of the lamp images 111 formed betweenthe optical unit 130 and the optical member 150 may be about double ofthe first number of the lamps 110, and the second luminance of the lampimages 111 is reduced in comparison with the first luminance of thelamps 110. As a result, a second interval between adjacent lamp images111 is smaller than a first interval between adjacent lamps 110.

Accordingly, the luminance distribution of light entering the opticalmember 150 becomes more uniform. The luminance distribution of lightentering optical member 150 may substantially reduce or eliminate thedetection of bright lines in the light transmitted through opticalmember 150.

Even though the second number of the lamp images 111 is about double thefirst number of the lamps 110, the bright lines may be detected in thelight transmitted through the optical member 150 when the secondluminance of the lamp images 111 is relatively high.

However, according to the present disclosure, a portion of the lightthat is incident onto the base 131 diffuses when exiting through theprotrusion portions 139 formed on the light-condensing portion 133.Thus, the amount of light refracted through the light-condensing portion133 toward the front direction of the optical unit 130 to form lampimages 111 is reduced. As a result the second luminance of the lampimages 111 decreases, and the detection of bright lines in the lighttransmitted through optical member 150 corresponding to the lamp images111 may be substantially reduced or prevented.

Accordingly, even though a distance between the lamps 110 and theoptical member 150 of the backlight assembly 100 may be shorter thanthat of a conventional backlight assembly (for example, the distance maybe about 9 mm or less), the bright lines may be reduced. Hence, thebacklight assembly 100 may be made relatively thin, compared toconventional backlight assemblies.

FIG. 7 is a cross-sectional view illustrating a position of a lamp image111 formed over an optical unit 130 of the backlight assembly 100 shownin FIG. 5. FIG. 8 is a graph illustrating a relationship between a firstdistance ‘Z’ and a second distance ‘D’ in FIG. 7.

Referring to FIGS. 7 and 8, the first distance ‘Z’ is defined as adistance from the lamps 110 to an upper face of the base 131 on whichthe light-condensing portion 133 is formed, and the second distance ‘D’is defined as a distance from an axis, which passes through a center ofthe lamp 110 and is substantially perpendicular to the base 131, to oneof the lamp images 111 associated with that lamp 110.

When the first distance ‘Z’ increases, the second distance ‘D’ alsoincreases. When the first distance ‘Z’ decreases, the second distance‘D’ also decreases. Thus, when the first distance ‘Z’ decreases, adistance between two lamp images 111 adjacent to each other, whichcorresponds to 2×x‘D’, decreases. When the distance between the two lampimages 111 becomes too small, the two lamp images 111 may be hard todistinguish from one another, so that the two lamp images 111 may berecognized as one image.

When the first distance ‘Z’ becomes too large, two lamp images 111adjacent to each other of four lamp images 111 generated from two lamps110 may be difficult to distinguish from one another.

Accordingly, the first distance ‘Z’ may be determined, such that thedistances between adjacent lamp images 111 may be substantially uniformand the lamp images 111, which have the second number that is greaterthan the first number of the lamps 110, may be formed to reduce thebright lines.

For example, in some embodiments, the distance between the lamps 110 andthe optical member 150 is no more than about 9 mm. The first distance‘Z’ is equal to the difference between the distance between the lamps110 and the optical member 150 and the distance between the opticalmember 150 and the optical unit 130.

Display Device

FIG. 9 is a cross-sectional view illustrating a display device accordingto an example embodiment of the present invention.

Referring to FIG. 9, a display device 600 includes a plurality of lightsources 610, an optical module 670 and a display panel 690.

The light sources 610 illustrated in FIG. 9 are substantially identicalto the light sources in FIGS. 5 to 8. Many types of light sources may beused.

The optical module 670 is disposed over the light sources 610 to formimages using light provided from the light sources 610. The number ofthe images is greater than the number of the light sources 610. Light, aluminance distribution of which is substantially uniform with respect toa front of the optical module 670, exits the optical module 670. Theoptical module 670 includes an optical unit 630 and an optical member650.

The optical unit 630 and the optical member 650 illustrated in FIG. 9are substantially identical to the optical unit 130 and the opticalmember 150, which are shown in FIGS. 5 to 8. However, otherconfigurations may be used (e.g., different numbers of protrusions 639,different shapes, different relative placements and sizes, etc.). Theoptical unit 630 may include a body 631, a light-condensing portion 633and protrusion portions 639, which correspond to the base 131, thelight-condensing member 133 and the protrusion members 139 shown in FIG.5, respectively.

Light is incident onto the body 631 and then passes through thelight-condensing portion 633. A portion of the light passing through thelight-condensing portion 633 is refracted and condensed in a frontdirection F of the optical unit 630. Thus, images 611 having a firstnumber are formed. The first number of the images 611 is greater than asecond number of the light sources 610. The images 611 are formedbetween the optical unit 630 and the optical member 650. Light passingthrough each of the protrusion portions 639 is scattered to exit theoptical unit 630.

The optical member 650 enhances optical characteristics, such as theluminance uniformity of light emitted from the optical unit 630, andthus light having the enhanced optical characteristics exits the opticalmember 650.

The optical module 670 optionally includes a light-condensing sheet 660.The light-condensing sheet 660 increases the front luminance of thelight by changing the optical path of the light to increase the portiontransmitted in the front direction F of display device 600.

The display panel 690 is disposed over the light-condensing sheet 660 todisplay an image using the light emitted from the light-condensing sheet660. The display panel 690 to includes a first substrate 691, a secondsubstrate 695 and a liquid crystal layer (not shown). The first andsecond substrates 691 and 695 face each other. The liquid crystal layeris disposed between the first and second substrates 691 and 695.

The first substrate 691 may include a plurality of first electrodes thatare arranged in a matrix configuration and a plurality of switchingelements each of which applies a predetermined voltage to correspondingfirst electrodes. The second substrate 695 may include a secondelectrode facing the first electrodes and a color filter for displayinga predetermined color using externally provided light.

When an electric power is applied to the first and second electrodes,electric fields are generated between the first and second electrodes.Molecules of the liquid crystal layer between the first and secondelectrodes are oriented according to the local electric field. Since theoptical transmissivity of the liquid crystal depends on the orientationof the molecules of the liquid crystal material, the displayed image maybe changed by changing the voltages applied to the electrodes of thedisplay panel 690.

According to the present disclosure, the optical unit condenses aportion of light emitted from light sources toward a front direction ofthe optical unit, and diffuses a remaining portion of the light. Thus,lamp images, the number of which is about double of the number of thelamps, are formed between the optical unit and the optical member.Hence, the backlight assembly having the above structure hassubstantially the same effect as a backlight assembly including a largernumber of light sources disposed at narrower intervals.

In addition, the luminance of the lamp images is reduced in comparisonwith the luminance of the lamps. Thus, bright lines generated on theoptical member decrease, and the display quality of a display devicehaving the optical unit may be enhanced.

Although the optical unit has been primarily discussed with reference tothe exemplary configuration of FIG. 1, other configurations may be used.For example, configurations with additional slant faces (e.g., as shownin FIGS. 2 and 3), configurations with a horizontal portion (e.g., asshown in FIG. 4), and configurations with curved surfaces (concaveand/or convex, as described above). For these different configurations,the associated light condensing portions condense light differently thanthe configuration of FIG. 1. For example, the configuration of FIG. 2may provide for four lamp images for each lamp, rather than two.

Although exemplary embodiments of the present invention have beendescribed, it is understood that the present invention should not belimited to these exemplary embodiments but various changes andmodifications can be made by one ordinary skilled in the art within thespirit and scope of the present invention as hereinafter claimed.

What is claimed is:
 1. An optical unit comprising: a base; alight-condensing member comprising a first curved slant face protrudingfrom the base and a second curved slant face protruding from the base,the second curved slant face being slated slanted toward the firstcurved slant face; and a plurality of protrusion members protruding froma surface of the light-condensing member such that adjacent protrusionmembers are spaced apart from each other to only partially cover thesurface of the light-condensing member.
 2. The optical unit of claim 1,wherein at least one of the first and second curved slant faces isconcave convex.
 3. The optical unit of claim 2, wherein the first andsecond curved slant faces are connected at a rounded top portion.
 4. Theoptical unit of claim 1, wherein the first curved slant face comprises afirst face protruding from the base to form a first angle with respectto the base and a second face extending from an upper portion of thefirst face to form a second angle with respect to the base, and thesecond curved slant face comprises a third face protruding from the basetoward the first face to form the first angle with respect to the baseand a fourth face extending from an upper portion of the third face tobe connected to the second face, the fourth face forming the secondangle with respect to the base.
 5. The optical unit of claim 4, whereinthe first angle is lager larger than the second angle.
 6. The opticalunit of claim 4, wherein the first and second faces are connected at afirst rounded portion, and the third and fourth faces are connected at asecond rounded portion.
 7. The optical unit of claim 6, wherein thefirst, second, third, and fourth faces respectively comprises a flatsurface.
 8. A backlight assembly comprising: a plurality of lightsources configured to generate light; and an optical unit to condenseand diffuse the light, the optical unit comprising: a base; alight-condens1ing portion comprising a first curved slant faceprotruding from the base and a second curved slant face protruding fromthe base, the second curved slant face being slated slanted toward thefirst curved slant face; and a plurality of protrusion portion portionsdisposed on a surface of the light-condensing portion such that adjacentprotrusion portions are spaced apart from each other to only partiallycover the surface of the light-condensing portion.
 9. The backlightassembly of claim 8, wherein the light sources have a first number andthe optical unit receives the light from the light sources to formimages of the light sources, the images having a second number that isgreater than the first number.
 10. The backlight assembly of claim 9,wherein the light-condensing portion is elongated along a longitudinaldirection of the light source.
 11. The backlight assembly of claim 9,wherein the first and second curved slant faces are connected at arounded top portion.
 12. The backlight assembly of claim 11, wherein thefirst curved slant face comprises a first face protruding from the baseto form a first angle with respect to the base and a second faceextending from an upper portion of the first face to form a second anglewith respect to the base, and the second curved slant face comprises athird face protruding from the base toward the first face to form thefirst angle with respect to the base and a fourth face extending from anupper portion of the third face to be connected to the second face, thefourth face forming the second angle with respect to the base, whereinthe first angle is larger than the second angle.
 13. The backlightassembly of claim 12, wherein the first and second faces are connectedat a first rounded portion, and the third and fourth faces are connectedat a second rounded portion.
 14. A display device comprising: aplurality of light sources to generate light; an optical module tocondense and diffuse the light, the optical module comprising an opticalunit including: a base; a light-condensing member comprising a firstcurved slant face protruding from the base and a second curved slantface protruding from the base, the second curved slant face being slatedslanted toward the first curved slant face; and a plurality ofprotrusion portion portions disposed on a surface of thelight-condensing portion, such that adjacent protrusion portions arespaced apart from each other to only partially cover the surface of thelight-condensing portion; and a display panel disposed over the opticalmodule to display an image using light from the optical module.
 15. Thedisplay device of claim 14, wherein the light sources have a firstnumber and the optical unit receives the light from the light sources toform images of the light sources, the images having a second number thatis greater than the first number.
 16. The display device of claim 15,wherein the optical module further comprises an optical memberconfigured to receive light from the optical unit to emit light havingsubstantially uniform luminance with respect to a front direction of thebase, wherein the images of the light sources are formed between theoptical unit and the optical member.
 17. The optical unit display deviceof claim 14, wherein the first and second curved slant faces areconnected at a rounded top portion.
 18. The display device of claim 17,wherein the first curved slant face comprises a first face protrudingfrom the base to form a first angle with respect to the base and asecond face extending from an upper portion of the first face to form asecond angle with respect to the base, and the second curved slant facecomprises a third face protruding from the base toward the first face toform the first angle with respect to the base and a fourth faceextending from an upper portion of the third face to be connected to thesecond face, the fourth face forming the second angle with respect tothe base, wherein the first angle is larger than the second angle. 19.The display device of claim 18, wherein the first and second faces areconnected at a first rounded portion, and the third and fourth faces areconnected at a second rounded portion.
 20. An optical unit comprising: abase; a light-condensing member comprising a first slant face protrudingfrom the base and a second slant face protruding from the base, thesecond slant face being slanted toward the first slant face, wherein thefirst and second slant faces are connected at a rounded top portion; anda plurality of protrusion members protruding from a surface of thelight-condensing member except for the top portion of thelight-condensing member.
 21. The optical unit of claim 20, wherein atleast one of the first and second slant faces is convex.
 22. The opticalunit of claim 20, wherein the rounded top portion has a radius ofcurvature of about 0.05 times to about 0.7 times a pitch of neighboringlight condensing members.
 23. The optical unit of claim 20, wherein thefirst slant face comprises a first face protruding from the base to forma first angle with respect to the base, and a second face extending froman upper portion of the first face to form a second angle with respectto the base, and the second slant face comprises a third face protrudingfrom the base toward the first face to form the first angle with respectto the base, and a fourth face extending from an upper portion of thethird face to be connected to the second face, the fourth face formingthe second angle with respect to the base.
 24. The optical unit of claim23, wherein the first angle is larger than the second angle.
 25. Theoptical unit of claim 23, wherein the first and second faces areconnected at a first rounded portion, and the third and fourth faces areconnected at a second rounded portion.
 26. The optical unit of claim 25,wherein the first, second, third, and fourth faces respectively compriseflat surfaces.
 27. The optical unit of claim 20, wherein thelight-condensing member has a surface roughness of about 0.1 to about 10micrometers root mean square.
 28. A backlight assembly comprising: aplurality of light sources configured to generate light; an optical unitto condense and diffuse the light, the optical unit comprising: a base;a light-condensing member comprising a first slant face protruding fromthe base and a second slant face protruding from the base, the secondslant face being slanted toward the first slant face, wherein the firstand second slant faces are connected at a rounded top portion; and aprotrusion member disposed on a surface of the light-condensing memberexcept for the top portion of the light-condensing member.
 29. Thebacklight assembly of claim 28, wherein the light sources comprise afirst number of the light sources, and the optical unit is configured toreceive the light from the light sources to form images of the lightsources, the images comprising a second number of the images that isgreater than the first number.
 30. The backlight assembly of claim 29,wherein the light-condensing member is elongated along a longitudinaldirection of the light source.
 31. The backlight assembly of claim 28,wherein the first slant face comprises a first face protruding from thebase to form a first angle with respect to the base and a second faceextending from an upper portion of the first face to form a second anglewith respect to the base, and the second slant face comprises a thirdface protruding from the base toward the first face to form the firstangle with respect to the base, and a fourth face extending from anupper portion of the third face to be connected to the second face, thefourth face forming the second angle with respect to the base, whereinthe first angle is larger than the second angle.
 32. The backlightassembly of claim 31, wherein the first and second faces are connectedat a first rounded portion, and the third and fourth faces are connectedat a second rounded portion.
 33. The backlight assembly of claim 28,wherein the rounded top portion has a radius of curvature of about 0.05times to about 0.7 times a pitch of neighboring light condensingmembers.
 34. The backlight assembly of claim 28, wherein thelight-condensing member has a surface roughness of about 0.1 to about 10micrometers root mean square.
 35. A display device comprising: aplurality of light sources for generating light; an optical module tocondense and diffuse the light, the optical module comprising an opticalunit including: a base; a light-condensing member comprising a firstslant face protruding from the base and a second slant face protrudingfrom the base, the second slant face being slanted toward the firstslant face, wherein the first and second slant faces are connected at arounded top portion; and a protrusion member disposed on a surface ofthe light-condensing member except for the top portion of thelight-condensing member; a display panel disposed over the opticalmodule to display an image using light from the optical module.
 36. Thedisplay device of claim 35, wherein the light sources comprise a firstnumber of the light sources, and the optical unit is configured toreceive the light from the light sources to form images of the lightsources, the images comprising a second number of the images that isgreater than the first number.
 37. The display device of claim 36,wherein the optical module further comprises an optical memberconfigured to receive light from the optical unit to emit light havingsubstantially uniform luminance with respect to a front direction of thebase, wherein the images of the light sources are formed between theoptical unit and the optical member.
 38. The display device of claim 37,wherein the distance between the light source and the optical member isno more than about 9 mm.
 39. The display device of claim 35, wherein thefirst slant face comprises a first face protruding from the base to forma first angle with respect to the base, and a second face extending froman upper portion of the first face to form a second angle with respectto the base, and the second slant face comprises a third face protrudingfrom the base toward the first face to form the first angle with respectto the base, and a fourth face extending from an upper portion of thethird face to be connected to the second face, the fourth face formingthe second angle with respect to the base, wherein the first angle islarger than the second angle.
 40. The display device of claim 39,wherein the first and second faces are connected at a first roundedportion, and the third and fourth faces are connected at a secondrounded portion.
 41. The display device of claim 35, wherein the roundedtop portion has a radius of curvature of about 0.05 times to about 0.7times a pitch of neighboring light condensing members.
 42. The displaydevice of claim 35, wherein the light-condensing member has a surfaceroughness of about 0.1 to about 10 micrometers root mean square.
 43. Anoptical unit comprising: a base; a light-condensing member comprising afirst slant face protruding from the base and a second slant faceprotruding from the base, the second slant face being slanted toward thefirst slant face; and a plurality of protrusion members protruding froma surface of the light-condensing member such that the light-condensingmember has a surface roughness of about 0.1 to about 10 micrometers rootmean square.
 44. The optical unit of claim 43, wherein at least one ofthe first and second slant faces is convex.
 45. The optical unit ofclaim 43, wherein the first and second slant faces are connected at arounded top portion.
 46. The optical unit of claim 45, wherein thelight-condensing member has a rounded top portion having a radius ofcurvature of about 0.05 times to about 0.7 times a pitch of neighboringlight condensing members.
 47. The optical unit of claim 43, wherein thefirst slant face comprises a first face protruding from the base to forma first angle with respect to the base, and a second face extending froman upper portion of the first face to form a second angle with respectto the base, and the second slant face comprises a third face protrudingfrom the base toward the first face to form the first angle with respectto the base, and a fourth face extending from an upper portion of thethird face to be connected to the second face, the fourth face formingthe second angle with respect to the base.
 48. The optical unit of claim47, wherein the first angle is larger than the second angle.
 49. Theoptical unit of claim 47, wherein the first and second faces areconnected at a first rounded portion, and the third and fourth faces areconnected at a second rounded portion.
 50. The optical unit of claim 49,wherein the first, second, third, and fourth faces respectively compriseflat surfaces.
 51. The optical unit of claim 43, wherein the protrusionmember is disposed on the surface of the light-condensing member exceptfor a top portion of the light-condensing member.
 52. A backlightassembly comprising: a plurality of light sources configured to generatelight; an optical unit to condense and diffuse the light, the opticalunit comprising: a base; a light-condensing member comprising a firstslant face protruding from the base and a second slant face protrudingfrom the base, the second slant face being slanted toward the firstslant face; and a protrusion member disposed on a surface of thelight-condensing member such that the light-condensing member has asurface roughness of about 0.1 to about 10 micrometers root mean square.53. The backlight assembly of claim 52, wherein the light sourcescomprise a first number of the light sources, and the optical unit isconfigured to receive the light from the light sources to form images ofthe light sources, the images comprising a second number of the imagesthat is greater than the first number.
 54. The backlight assembly ofclaim 53, wherein the light-condensing member is elongated along alongitudinal direction of the light source.
 55. The backlight assemblyof claim 52, wherein the first and second slant faces are connected at arounded top portion.
 56. The backlight assembly of claim 55, wherein thefirst slant face comprises a first face protruding from the base to forma first angle with respect to the base, and a second face extending froman upper portion of the first face to form a second angle with respectto the base, and the second slant face comprises a third face protrudingfrom the base toward the first face to form the first angle with respectto the base, and a fourth face extending from an upper portion of thethird face to be connected to the second face, the fourth face formingthe second angle with respect to the base, wherein the first angle islarger than the second angle.
 57. The backlight assembly of claim 56,wherein the first and second faces are connected at a first roundedportion, and the third and fourth faces are connected at a secondrounded portion.
 58. The backlight assembly of claim 55, wherein thelight-condensing member has a rounded top portion having a radius ofcurvature of about 0.05 times to about 0.7 times a pitch of neighboringlight condensing members.
 59. The backlight assembly of claim 52,wherein the protrusion member is disposed on the surface of thelight-condensing member except for a top portion of the light-condensingmember.
 60. A display device comprising: a plurality of light sources togenerate light; an optical module to condense and diffuse the light, theoptical module comprising an optical unit including: a base; alight-condensing member comprising a first slant face protruding fromthe base and a second slant face protruding from the base, the secondslant face being slanted toward the first slant face; and a protrusionmember disposed on a surface of the light-condensing member such thatthe light-condensing member has a surface roughness of about 0.1 toabout 10 micrometers root mean square; a display panel disposed over theoptical module to display an image using light from the optical module.61. The display device of claim 60, wherein the light sources comprise afirst number of the light sources, and the optical unit is configured toreceive the light from the light sources to form images of the lightsources, the images comprising a second number of the images that isgreater than the first number.
 62. The display device of claim 61,wherein the optical module further comprises an optical memberconfigured to receive light from the optical unit to emit light havingsubstantially uniform luminance with respect to a front direction of thebase, wherein the images of the light sources are formed between theoptical unit and the optical member.
 63. The display device of claim 62,wherein the distance between the light source and the optical member isno more than about 9 mm.
 64. The display device of claim 60, wherein thefirst and second slant faces are connected at a rounded top portion. 65.The display device of claim 64, wherein the first slant face comprises afirst face protruding from the base to form a first angle with respectto the base, and a second face extending from an upper portion of thefirst face to form a second angle with respect to the base, and thesecond slant face comprises a third face protruding from the base towardthe first face to form the first angle with respect to the base, and afourth face extending from an upper portion of the third face to beconnected to the second face, the fourth face forming the second anglewith respect to the base, wherein the first angle is larger than thesecond angle.
 66. The display device of claim 65, wherein the first andsecond faces are connected at a first rounded portion, and the third andfourth faces are connected at a second rounded portion.
 67. The displaydevice of claim 64, wherein the light-condensing member has a roundedtop portion having a radius of curvature of about 0.05 times to about0.7 times a pitch of neighboring light condensing members.
 68. Thedisplay device of claim 60, wherein the protrusion member is disposed onthe surface of the light-condensing member except for a top portion ofthe light-condensing member.
 69. An optical unit comprising: a base; alight-condensing member comprising a first slant face protruding fromthe base and a second slant face protruding from the base, the secondslant face being slanted toward the first slant face; and a plurality ofprotrusion members protruding from a surface of the light-condensingmember, wherein the light-condensing member has a rounded top portionhaving a radius of curvature of about 0.05 times to about 0.7 times apitch of neighboring light condensing members.
 70. The optical unit ofclaim 69, wherein at least one of the first and second slant faces isconvex.
 71. The optical unit of claim 70, wherein the light-condensingmember has a rounded bottom portion having a radius of curvature ofabout 0.05 times to about 0.7 times a pitch of neighboring lightcondensing members.
 72. The optical unit of claim 69, wherein the firstslant face comprises a first face protruding from the base to form afirst angle with respect to the base, and a second face extending froman upper portion of the first face to form a second angle with respectto the base, and the second slant face comprises a third face protrudingfrom the base toward the first face to form the first angle with respectto the base, and a fourth face extending from an upper portion of thethird face to be connected to the second face, the fourth face formingthe second angle with respect to the base.
 73. The optical unit of claim72, wherein the first angle is larger than the second angle.
 74. Theoptical unit of claim 72, wherein the first and second faces areconnected at a first rounded portion, and the third and fourth faces areconnected at a second rounded portion.
 75. The optical unit of claim 74,wherein the first, second, third, and fourth faces respectively compriseflat surfaces.
 76. The optical unit of claim 69, wherein the protrusionmembers are disposed on the surface of the light-condensing memberexcept for a top portion of the light-condensing member.
 77. The opticalunit of claim 69, wherein the protrusion members are disposed such thatthe light-condensing member has a surface roughness of about 0.1 toabout 10 micrometers root mean square.
 78. A backlight assemblycomprising: a plurality of light sources configured to generate light;an optical unit to condense and diffuse the light, the optical unitcomprising: a base; a light-condensing member comprising a first slantface protruding from the base and a second slant face protruding fromthe base, the second slant face being slanted toward the first slantface; and a protrusion member disposed on a surface of thelight-condensing member, wherein the light-condensing member has arounded top portion having a radius of curvature of about 0.05 times toabout 0.7 times a pitch of neighboring light condensing members.
 79. Thebacklight assembly of claim 78, wherein the light sources comprise afirst number of the light sources, and the optical unit is configured toreceive the light from the light sources to form images of the lightsources, the images comprising a second number of the images that isgreater than the first number.
 80. The backlight assembly of claim 79,wherein the light-condensing member is elongated along a longitudinaldirection of the light source.
 81. The backlight assembly of claim 79,wherein the light-condensing member has a rounded bottom portion havinga radius of curvature of about 0.05 times to about 0.7 times a pitch ofneighboring light condensing members.
 82. The backlight assembly ofclaim 81, wherein the first slant face comprises a first face protrudingfrom the base to form a first angle with respect to the base, and asecond face extending from an upper portion of the first face to form asecond angle with respect to the base, and the second slant facecomprises a third face protruding from the base toward the first face toform the first angle with respect to the base, and a fourth faceextending from an upper portion of the third face to be connected to thesecond face, the fourth face forming the second angle with respect tothe base, wherein the first angle is larger than the second angle. 83.The backlight assembly of claim 82, wherein the first and second facesare connected at a first rounded portion, and the third and fourth facesare connected at a second rounded portion.
 84. The backlight assembly ofclaim 78, wherein the protrusion member is disposed on the surface ofthe light-condensing member except for a top portion of thelight-condensing member.
 85. The backlight assembly of claim 78, whereinthe protrusion member is disposed such that the light-condensing memberhas a surface roughness of about 0.1 to about 10 micrometers root meansquare.
 86. A display device comprising: a plurality of light sources togenerate light; an optical module to condense and diffuse the light, theoptical module comprising an optical unit including: a base; alight-condensing member comprising a first slant face protruding fromthe base and a second slant face protruding from the base, the secondslant face being slanted toward the first slant face, wherein thelight-condensing member has a rounded top portion having a radius ofcurvature of about 0.05 times to about 0.7 times a pitch of neighboringlight condensing members; and a protrusion member disposed on a surfaceof the light-condensing member; a display panel disposed over theoptical module to display an image using light from the optical module.87. The display device of claim 86, wherein the light sources comprise afirst number of the light sources, and the optical unit is configured toreceive the light from the light sources to form images of the lightsources, the images comprising a second number of the images that isgreater than the first number.
 88. The display device of claim 87,wherein the optical module further comprises an optical memberconfigured to receive light from the optical unit to emit light havingsubstantially uniform luminance with respect to a front direction of thebase, wherein the images of the light sources are formed between theoptical unit and the optical member.
 89. The display device of claim 88,wherein the distance between the light source and the optical member isno more than about 9 mm.
 90. The display device of claim 86, wherein thelight-condensing member has a rounded bottom portion having a radius ofcurvature of about 0.05 times to about 0.7 times a pitch of neighboringlight condensing members.
 91. The display device of claim 90, whereinthe first slant face comprises a first face protruding from the base toform a first angle with respect to the base, and a second face extendingfrom an upper portion of the first face to form a second angle withrespect to the base, and the second slant face comprises a third faceprotruding from the base toward the first face to form the first anglewith respect to the base, and a fourth face extending from an upperportion of the third face to be connected to the second face, the fourthface forming the second angle with respect to the base, wherein thefirst angle is larger than the second angle.
 92. The display device ofclaim 91, wherein the first and second faces are connected at a firstrounded portion, and the third and fourth faces are connected at asecond rounded portion.
 93. The display device of claim 86, wherein theprotrusion member is disposed on the surface of the light-condensingmember except for a top portion of the light-condensing member.
 94. Thedisplay device of claim 86, wherein the protrusion member is disposedsuch that the light-condensing member has a surface roughness of about0.1 to about 10 micrometers root mean square.